#include<stdio.h>
#include<stdlib.h>
#include<string.h>


int main(int argc, char *argv[])
{
  if(argc != 2)
  {
    printf("can not execute!!!\n");
    exit(1);
  }

  if(strcmp(argv[1], "-a") == 0)
  {
    printf("hello a\n");
  }
  else if(strcmp(argv[1],"-b") == 0)
  {
    printf("hello b\n");
  }
  else 
  {
    printf("hello c\n");
  }
  return 0;
}
